Immune globulin products from human plasma were first used in 1952 to treat immune deficiency. Initially, intramuscular or subcutaneous administration of Immunoglobulin isotype G (IgG) were the methods of choice. For injecting larger amounts of IgG necessary for effective treatment of various diseases, however, the intravenous administrable products with lower concentrated IgG (50 mg/mL) were developed. Usually intravenous immunoglobulin (IVIG), contains the pooled immunoglobulin G (IgG) immunoglobulins from the plasma of more than a thousand blood donors. Typically containing more than 95% unmodified IgG, which has intact Fc-dependent effector functions, and only trace amounts of immunoglobulin A (IgA) or immunoglobulin M (IgM), IVIGs are sterile, purified IgG products primarily used in treating three main categories of medical conditions: (1) immune deficiencies such as X-linked agammaglobulinemia, hypogammaglobulinemia (primary immune deficiencies), and acquired compromised immunity conditions (secondary immune deficiencies), featuring low antibody levels; (2) inflammatory and autoimmune diseases; and (3) acute infections.
Specifically, many people with primary immunodeficiency disorders lack antibodies needed to resist infection. In certain cases these deficiencies can be supplemented by the infusion of purified IgG, commonly through intravenous administration (i.e., IVIG therapy). Several primary immunodeficiency disorders are commonly treated in the fashion, including X-linked Agammaglobulinemia (XLA), Common Variable Immunodeficiency (CVID), Hyper-IgM Syndrome (HIM), Severe Combined Immunodeficiency (SCID), and some IgG subclass deficiencies (Blaese and Winkelstein, J. Patient & Family Handbook for Primary Immunodeficiency Diseases. Towson, Md.: Immune Deficiency Foundation; 2007).
While IVIG treatment can be very effective for managing primary immunodeficiency disorders, this therapy is only a temporary replacement for antibodies that are not being produced in the body, rather than a cure for the disease. Accordingly, patients dependent upon IVIG therapy require repeated doses, typically about once a month for life. This need places a great demand on the continued production of IVIG compositions. However, unlike other biologics that are produced via in vitro expression of recombinant DNA vectors, IVIG is fractionated from human blood and plasma donations. Thus, IVIG products cannot be increased by simply increasing the volume of production. Rather the level of commercially available IVIG is limited by the available supply of blood and plasma donations.
Several factors drive the demand for IVIG, including the acceptance of IVIG treatments, the identification of additional indications for which IVIG therapy is effective, and increasing patient diagnosis and IVIG prescription. Notably, the global demand for IVIG has more than quadrupled since 1990 and continues to increase today at an annual rate between about 7% and 10% (Robert P., Pharmaceutical Policy and Law, 11 (2009) 359-367). For example, the Australian National Blood Authority reported that the demand for IVIG in Australia grew by 10.6% for the 2008-2009 fiscal year (National Blood Authority Australia Annual Report 2008-2009).
Due in part to the increasing global demand and fluctuations in the available supply of immunoglobulin products, several countries, including Australia and England, have implemented demand management programs to protect supplies of these products for the highest demand patients during times of product shortages.
It has been reported that in 2007, 26.5 million liters of plasma were fractionated, generating 75.2 metric tons of IVIG, with an average production yield of 2.8 grams per liter (Robert P., supra). This same report estimated that global IVIG yields are expected to increase to about 3.43 grams per liter by 2012. However, due to the continued growth in global demand for IVIG, projected at between about 7% and 13% annually between now and 2015, further improvement of the overall IVIG yield will be needed to meet global demand.
A number of IVIG preparation methods are used by commercial suppliers of IVIG products. One common problem with the current IVIG production methods is the substantial loss of IgG during the purification process, estimated to be at least 30% to 35% of the total IgG content of the starting material. One challenge is to maintain the quality of viral inactivation and lack of impurities which can cause adverse reactions, while bolstering the yield of IgG. At the current production levels of IVIG, what may be considered small increases in the yield are in fact highly significant. For example at 2007 production levels, a 2% increase in efficiency, equal to an additional 56 milligrams per liter, would generate 1.5 additional metric tons of IVIG.
In the fourth installment of a series of seminal papers published on the preparation and properties of serum and plasma proteins, Cohn et al. (J. Am. Chem. Soc., 1946, 68(3): 459-475) first described a methods for the alcohol fractionation of plasma proteins (method 6), which allows for the isolation of a fraction enriched in IgG from human plasma. Several years later, Oncley et al. (J. Am. Chem. Soc., 1949, 71(2): 541-550) expanded upon the Cohn methods by publishing a method (method 9) that resulted in the isolation of a purer IgG preparation.
These methods, while laying the foundation for an entire industry of plasma derived blood factors, were unable to provide IgG preparations having sufficiently high concentrations for the treatment of several immune-related diseases, including Kawasaki syndrome, immune thrombocytopenic purpura, and primary immune deficiencies. As such, additional methodologies employing various techniques, such as ion exchange chromatography, were developed to provide higher purity and higher concentration IgG formulations. Hoppe et al. (Munch Med Wochenschr 1967 (34): 1749-1752) and Falksveden (Swedish Patent No. 348942) and Falksveden and Lundblad (Methods of Plasma Protein Fractionation 1980) were among the first to employ ion exchange chromatography for this purpose.
Various modern, methods employ a precipitation step, such as caprylate precipitation (Lebing et al., Vox Sang 2003 (84):193-201) and Cohn Fraction (I+)II+III ethanol precipitation (Tanaka et al., Braz J Med Biol Res 2000 (33)37-30) coupled to column chromatography. Most recently, Teschner et al. (Vox Sang, 2007 (92):42-55) have described a method for production of a 10% IVIG product in which cryo-precipitate is first removed from pooled plasma and then a modified Cohn-Oncley cold ethanol fractionation is performed, followed by S/D treatment of the intermediate, ion exchange chromatography, nanofiltration, and optionally ultrafiltration/diafiltration.
However, despite the improved purity, safety, and yield afforded by these IgG manufacturing methods, a significant amount of IgG is still lost during the purification process. For example, Teschner et al. report that their method results in an increased IgG yield of 65% (Teschner et al., supra). As reported during various plasma product meetings, the average yields for large-scale preparation of IgG, such as from Baxter, CSL Behring, Upfront Technology, Cangene, Prometric BioTherapeutics, and the Finnish Red Cross, range from about 61% to about 65% in the final container. This represents a loss of at least about a third of the IgG present in the pooled plasma fraction during the manufacturing process.
As such, a need exists for improved and more efficient methods for manufacturing IVIG products. The present invention satisfies these and other needs by providing IVIG manufacturing methods that produce yields that are at least 6 to 10% higher than currently achievable, as well as IVIG compositions provided there from.